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usb: dwc3: ulpi: Use VStsDone to detect PHY regs access completion

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commit ce722da66d3e9384aa2de9d33d584ee154e5e157 upstream.

In accordance with [1] the DWC_usb3 core sets the GUSB2PHYACCn.VStsDone
bit when the PHY vendor control access is done and clears it when the
application initiates a new transaction. The doc doesn't say anything
about the GUSB2PHYACCn.VStsBsy flag serving for the same purpose. Moreover
we've discovered that the VStsBsy flag can be cleared before the VStsDone
bit. So using the former as a signal of the PHY control registers
completion might be dangerous. Let's have the VStsDone flag utilized
instead then.

[1] Synopsys DesignWare Cores SuperSpeed USB 3.0 xHCI Host Controller
    Databook, 2.70a, December 2013, p.388

Fixes: 88bc9d194f ("usb: dwc3: add ULPI interface support")
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20201210085008.13264-2-Sergey.Semin@baikalelectronics.ru
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Serge Semin 2020-12-10 11:50:06 +03:00 committed by Greg Kroah-Hartman
parent 8907a10c8f
commit b51963e9f5
2 changed files with 2 additions and 1 deletions
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1
drivers/usb/dwc3/core.h
View File

@ -285,6 +285,7 @@
/* Global USB2 PHY Vendor Control Register */
#define DWC3_GUSB2PHYACC_NEWREGREQ BIT(25)
#define DWC3_GUSB2PHYACC_DONE BIT(24)
#define DWC3_GUSB2PHYACC_BUSY BIT(23)
#define DWC3_GUSB2PHYACC_WRITE BIT(22)
#define DWC3_GUSB2PHYACC_ADDR(n) (n << 16)

2
drivers/usb/dwc3/ulpi.c
View File

@ -24,7 +24,7 @@ static int dwc3_ulpi_busyloop(struct dwc3 *dwc)
while (count--) {
reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYACC(0));
if (!(reg & DWC3_GUSB2PHYACC_BUSY))
if (reg & DWC3_GUSB2PHYACC_DONE)
return 0;
cpu_relax();
}